you can't pin a message sent by webhook

[Majoramari]

Please describe the problem you are having in as much detail as possible:
you can't pin a message sent by webhook

Include a reproducible code sample here, if possible:

const webmessage = await webhookClient.send('', {
            username: `${message.guild.name}'s music service`,
            avatarURL: `${icon}`,
            embeds: [embed],
        });
webmessage.pin();

Further details:

• discord.js version: 12.3.1
• Node.js version: 14.8.0
• Operating system: windows 10 home, also linux debian 10
• Priority this issue should have – please be realistic and elaborate if possible: Not very important

Relevant client options:

• partials: CHANNEL, GUILD_MEMBER, MESSAGE, REACTION, USER
• gateway intents: none
• other: none

• [ x] I have also tested the issue on latest master, commit hash:

[almostSouji]

Webhook#send returns a discord.js Message instance, which has the pin message
WebhookClient#send does not and instead returns the raw API message data

For now you can work around this by fetching a Webhook instance from Guild/TextChannel#fetchWebhooks instead

We can reproduce this in our resource webhook project as well. https://github.com/discordjs/resource-webhooks/blob/main/src/index.ts#L73-L77

This is neither reflected in typings nor documented, typings show a Message instance, documentation suggests implementation of Webhook#send which also documents Message

[almostSouji]

Please keep this issue open, the typings are wrong and what the inheritance suggests documentation wise isn't intuitive either.
If you don't want to be notified you can set that in the right pane of the issue view.

[SpaceEEC]

This seems to have been resolved, typings-wise with #5223, and documentation-wise with #5712. 🎉